Manufacture of light-sensitive materials



Jan. 5, 1937. w. DIETr-:RLE Er AL 2,066,958

I MANUFACTURE OF LIGHT SENSITIVE MATERIALS i Filed March 1o, 195s ily?FERC/1.403675 Eg 3 I l/l/- Patented Jan. 5, 1937 UNITED STATES PATENTGFFICE l MANUFACTURE 0F LIGHT-SENSITIVE MATERIAL Walter Dieterle andWalter Zeh, Dessau in Anhalt, and Werner Zerweck, Frankfort-amtlic-Main-Fechenheim, Germany, assignors to Agfa Ansco Corporation,Binghamton, N. Y., a corporation o! New York Application March 10, 1933,Serial No. 660,287 In Germany March 27, 1931 5 Claims.

(the quiuoline nucleus being linked in 2 or 4position) Y=S, Se Y=S, Se,C(CH3)2,O R W=H. N( alkyl, alkoxyl,

Rl r and r=alkyl R=H, alkyl, aryl, ac R'=H, alkyl n=O or 1 X=halide,perchlorate, alkylosulfate, paratoluene sulfonate, nitrate, or anothersuitable anion, are particularly suited for sensitizing photographicemulsions. The dyes are characterized by their sensitizing eiiiciencyand their stability against agents used for stabilizing the emulsions,for instance, potassium bromide.

In the appended claims the expression an amino group is to be understoodas including not only the amino group but also substituted amino groups.

The amino group having the radicals R. and R may be introduced at anypositionof the nuclei, the 5 and 6 positions are preferred for thenuclei of the kind of the benzthiazole nucleus; in the case of thequnoline nucleus the 6 and 'l positions are preferred. There may furtherbe present in the nuclei monovalent radicals, e. g. alkyl, alkoxyl,halide in any possible position.

(ci. ssa-7) The unsymmetrical character o! the dyes may have variouscauses. For instance, Y may diner from Y', or if Y and Y' represent thesame radical, W may be different from the group for instance, H; or ii Yand-Y' represent the same radical and W represents the two /a N\ groupsmay be linked in different positions. These possibilities are o; courseonly a few o! those which are includedf'within this invention.

The general Formula 1 comprises three principal groups of cyanines dyes:

Trimethinecyanines of the Formula 2,

4 Y (the qulnollne W 3 ne hema 2 A 2 linked in 2 or a 1 4poe1tlon) N N lr' pseudocyanlnes of the Formula 3,

R Y 4 \N 1 H R/ ajo 2 l and isocyanines of the Formula 4.

may represent H; or alkyl, for instance, methyl or ethyl; or aryl, forinstance, phenyl, naphthyl; or a substituted aryl;y or acyl, forinstance, benzoyl, acetyl, propionyl or butyryl. R may be alkyl in thecase of R being alkyl or aryl, or R is hydrogen in the case of R beinghydrogen or acyl. X may represent any suitable anion that willprecipitate the dye, for instance, a halide, perchlorate, alkylosulfate,paratoluene sulfonate, nitrate. r and r represent alkyl, for' instance,methyl, ethyl, propyl, butyl, amyl and th isomers of propyl butyl andamyl. W may be H; or

or alkyl, for instance, methyl or ethyl; or alkoxyl, for instance,methoxy or ethoxy.

The benzthiazole nucleus or the benzselenazole nucleus may containbesides the amino group one or several alkyl groups, such as methyl orethyl groups, or alkoxyl groups, such as methoxy or ethoxy groups, orboth alkyl and alkoxyl groups.

The introduction of the amino group into the benzthiazole nucleus causesa displacement of the range of sensitivity of the dyes towards theregion of longer waves. For instance, the introduction of onediethylamino group into the benzthiazole nucleus of an unsymmetricaltrimethinecyanine corresponding with the Formula 2 effects adisplacement of the maximum of sensitization of about 30ML towardslonger waves and when introduced into a benzselenazole nucleus onediethylamino group effects a displacement of the maximum ofsensitization of about 28ML.

As seen there is a slight difference between the replacement of hydrogenin the benzene nucleus by a substituted amino amino group in themolecule of the thiocyanines and the selenocyanines. It is to beunderstood that the foregoing statement is given only by way of example.Other radicals which have already been mentioned may represent R and R.The replacement of 1 and r by different radicals is of minor elciencyfor displacing the range of sensitlvity. The radicals representing X areof no inuence in the purpose set forth. The influence on thedisplacement of the sensitization maximum and on the intensity of thesensitivity can easily be determined by a few comparative experiments.

In Figs. 1 to 3 of the accompanying drawing there are shown spectrogramsof emulsions sensitized in accordance with the invention.

Fig. 1 shows the spectrogram of a silver halide emulsion sensitized with1.l'diethyl5diethyl amino benzthio-benzselenocarbocyanine iodide,

Fig. 2 shows the spectrogram of a silver halide emulsion sensitized with1.1'diethyl6.5'bis diethylamino-benzthiocarbocyanine perchlorate, and

Fig. 3 shows the spectrogram of a silver halide emulsion sensitized with1.1diethyl6diethyl amino-5-ethoxy-benzthiocarbccyanine perchlorate.

The dyes are obtainable according to the desired solubility in form ofthe bromide, iodide, perchlorate etc. and are used in a quantity asusual for the known sensitizing dyes. tity amounts to 8 to 25 milligramsper 1 kg. of

emulsion ready for being cast which containsabout 9 per cent of gelatin,4.5 per cent of silverhalide, the rest being water. We do not wish tolimit our invention exactly to the quantities just This quani indicated,the most suitable amount will be found in each particular case by a fewsimple experiments. 'Ihe dyes may be added to the emulsion in form ofsolutions. Suitable solvents are the alcohols, for instance, methyl orethyl alcohol, which may be used anhydrous or diluted with water. Thedyes may be added to the emulsion during any stage of its production,however, they are preferably added to the nished emulsion bei'ore beingcast. 'I'he dyes may likewise be added by coating the emulsion with themor by bathing the ilnished photographic materials in a bath in which thedye is dissolved.

'I'he production of the 4, 5, 6, or 7amino substituted2-methyl-benzthlazoles serving as a starting material for preparing thedyes is described in Examples 1 to 9. Other bases than those describedin these examples may be produced in an analogous manner. The method ofpreparing our new dyes from the bases is analogous to known methods andillustrate'd in Examples 10 to 20.

'Example 1.The preparation of 2-methyl-6- amino-benzo-thiazolecorresponding with the formula is described in U. S. Patent 1,758,385and reference is made thereto.

Example 2.-'1'he base 2methyl5amino benzthiazole corresponding with theformula can be obtained in two Ways.

. According to the rst way we proceed as follows: 2amino 4acetylamino-toluol corresponding with the formula \COCH| is firstrhodanatedI with NH4 SCN and Br in its methyl-alcoholic solution in themanner described in U. S. Patent 1,787,315 and then with anaqueousammoniacal solution. 'I'he formed I5 spaanse product, probably the2.5-diamino-6-methylbenzthiaaole corresponding with the formula The zincmercaptide of this compound is transformed into the2.6-dimethyl-5-acetylaminobenzthiazole with a melting point of about 178C. corresponding with the above formula by'heating the aforesaidmercaptide with acetic anhydride.

According to the second way 3-chloro-4- acetylamino-6-nitrotoluenehaving a melting point oi 143 C. is transformed into 2.6-dimethyl-5-nitro-benzthiazole forming compact, colorless crystals whencrystallized from alcohol which melt at about 106 C. This compoimdyields the 2.6 -dimethyl-5-amino-benzthiazole when reduced with iron andacetic acid, forming colorless crystals which melt at about 143 C. 'Ihethiazole can be easily acetylated.

Example 4.-The base 2.4-dimethyl-6-aminobenzthiazole corresponding withthe formula HaN ,e 7

4 I13%-CHI is obtained as follows. Acetyl-toluylene-diaminecorresponding with the formula NH: H

inc-oc/ is by means of SnClz transformed into the4thiazthionium-compound in the manner described in U. S. Patent1,637,023. pound with a solution of caustic alkali according to U. S.Patent 1,243,710 the corresponding o-amino-mercaptane corresponding withthe` formula C Hz When treating this c0111-,v

2.4-dimethyl-G-amino-benzthazole which forms colorless crystals meltingat about 118 C.

Example 5.-The base 2.4.6-trimethyl-7-ami-- no-benz-thiazolecorresponding Awith the formula HaC- 6 7 5 2i 4 3/ CH;

is obtainable as follows. Amino-acetylaminoxylidin corresponding withthe formula' CHI BaN-

benzthiazole corresponding with the formula mc s l 2 Isl/om,

and melting at about 285 C. is obtained. By boiling this compound with astrong aqueous solution of caustic alkali according to U. S. Patent1,788,297 it is split up 'to the corresponding o-amino-mercaptane, whichmay be separated from the reaction mixture in form of the zincmercaptide. By heating with acetic anhydride the 2.4.6-trimethyl- 7acetylarnino-benzthiazole is obtainable. After recrystallization fromits alcoholic solution this compound forms colorless crystals melting atabout 208 C. By saponification with hydrochloric acid the2.4.6-trimethyl- 7-amino-benzthiazo1e isv obtainable in form ofcolorless crystals melting at about 128 C.

Example iL-The base 2methy16dimethylam ino-benzthiazole correspondingwith ythe formula 4H* Is-CB.

has already been described: cf. Bernthsen, Ann. 251, `page 29.

Example 7.--The base 2-methyl-6-diethyl-amino-benztliiazolecorresponding with the formula ai om is obtainable analogously to thepreparation of 'the dimethyl compound (cfrY Example 1).'Ifhe' chlorideiormingnoolorless crystals is easily soluble in water and'decomposeswhen heated to a temperature of about 160 C. under strong evolution ofgas. 1f the lbase is set free from. the chloride by means of an-aqueoussolution of caustic alkali it separates in form' of a yellow oil whichsolidies when cooling.

Example 8.l-The base 2-methyl-5-dimethylamino-benzthiazole correspondingWith the formula I6 i (cnam-54 1%;41113 amino-benzthiazole correspondingwith the formula N-6 s 1 HC 2 1% fCHa is obtainable by heating2-amino-3-methyl-5- phenylamino-thiophenol-zinc (cf. U. S. Patent1,566,384) with acetic anhydridc. After crystallizing the compound frombenzene it forms colorless crystals Which melt at about 138 C. and areeasily soluble in benzene, alcohol and glacial acetic acid.

Example 10.-For .producing the dye [3-ethyl- 5 diethylamino benzthiazole(2) [3ethy16 ethoxy benzthiazole(2),] -trlmethine cyanineperchloratecorresponding with the formula s 7 6 oClHs Cgi 010| we proceed asfollows:

A. 9 grams of 5-diethylamino-Z-methyl-benzthiazole ethyl-iodide and 6.5grams of diphenylformamidine are intimately mixed; to this mixturc 25cc. of acetic anhydride are added and the whole is boiled for 3A hourunder reflux (about 140 C.). After cooling the reaction mixture ether isadded drop by drop while stirring the mixture and rubbing the walls ofthe vessel. This procedure is continued until the formation of crystalsoccurs at the walls of the vessel. Now, the dye is precipitated bycooling the reaction mixture with a freezing mixture and filtered off.The intermediate product which melts in its pure state at 218 to 219 C.corresponds probably with the formula B. 4 grams of the intermediateproduct arel boiled with 2 grams of2-methy1-6-ethoxy-benzthiazole-ethyl-iodide and 20 cc. of pyridine for1%; hour under reiiux (about 125 to 130 C. The dye is then precipitatedby addition of a few cc. of an aqueous solution of potassium iodide ofl0 per cent strength and water, separated by filtration, dissolved inalcohol and precipitated from its alcoholic solution in form of itsperchlorate by addition of a few cc. of an aqueous solution of sodiumperchlorate of 1 per cent strength and water.

After recrystallization of the dye, its alcoholic solution shows anabsorption maximum at a wave length of about 600ml.

Incorporated in a gelatino-silver-bromide emulsion containing about 4per cent of silver iodide the dye imparts to it a range of sensitivityfrom about 500ML to about '725ml with a maximum at about 625ml.

Example 11.-For producing the dye [3-ethyl- S-diethylamino benzthiazole(2 )l 3 ethylbenzthiazole- (2) ]-trimethinecyanine-perchloratecorresponding with the formula 4 grams of the intermediate productobtainable ethyl-iodide and diphenyl-formamidine in the manner describedin Example 10 sub A, are boiled with 2 grams of2-methyl-benzthiazole-ethyliodide and cc. of pyridine for 3A hour underreflux (125 to 130 C.). The reaction mixture is worked up in the mannerindicated in Example 10.

The dye shows in its alcoholic solution an absorption maximum at a wavelength of about 595ML. v

Incorporated in a gelatino-silver-bromide emulsion containing about 4per cent of silver iodide the dye imparts to it a range of sensitivityfrom about 510ml to about 720ML with a maximum at about G/m.

Example 12.-The dye [3-ethyl-6-diethylamino-benzthiazole-(Z) 3ethyl-benzelenazole- (2) l trimethinecyanine-iodide corresponding withthe formula is produced in the same manner as described in the foregoingexamples by starting from the corresponding materials.

The dye shows in its alcoholic solution an absorption maximum at a wavelength of about 600ML.

Incorporated in a gelatino-silver-bromide emulsion containing about 4per cent of silveriodide the dye imparts to it a range of sensitivityfrom about 510ml to about 715W with a maximum at about 630ml.

Example 13.-The dye [3-ethyl-5-diethylaminobenzthiazole(2)l[3-ethyl-6-diethylamino- Aso ' benzthiazole- (2)l-trimethinecyanine-perchlorate corresponding with the formula may beproduced by mixing 1.5 grams of the intermediate product described inExample 10 with 2.3 grams ofG-diethylamino-Z-methylbenzothiazole-ethyl-iodide and 15 cc. ofpyridine, boiling this mixture for 3A hour under reflux and working upthe reaction mixture as indicated in Example 10. The dye may likewise beobtained as iodide.

The alcoholic solution of the dye has an `absorption maximum at a wavelength of about 625ML.

Incorporated in a gelatino-silver-bromide emulsion containing about 4per cent of silver iodide the dye imparts to it a range of sensitivityfrom about 510W. to about 730ML with a maximum at about 655ML. Example14,-For producing [3-ethyl-5-diethylamino benzthiazole (2)] [1-ethylquinoline- (2) -trimethinecyanine iodide corresponding with the formula/7\ S /4\ 5 1 n H nl 2 2 1 (einem 4 a/ t1-t I? s I/HB\I 02H5 5 grams ofthe intermediate product obtainable from -diethylamino -2methylbenzthiazoleethyl-iodide and diphenyl-formamidine as described inExample 10, are boiled for 2% hours with 4 grams ofquinaldine-ethyl-iodide and 15 cc. of pyridine under reflux. The dyewhich forms is precipitated by addition of a few cc. of an aqueoussolution-of potassium iodide of per cent strength and water and isrecrystallized from alcohol.

The alcoholic solution of the dye has an absorption maximum at a wavelengthy of about 615m.

Incorporated in a gelatino-silver-bromide emulsion containing about 4per cent of silver iodide the dye imparts to it a range of sensitivenessfrom about 515W. to about 730ml. with a very flat maximum at about645W..

Example 15.-For producing the dye [Ii-ethyl--diethylamino-benzthiazole-(2) l-[3-methyl-in dole- (2)l-trimethinecyanine iodide corresponding with the formula metricalcarbo-cyanine from trimethyl-indol-- ethyl iodide may be removed byfractional crystallization.

In its alcoholic solution the dye shows an absorption maximum at a wavelength of about 585ML.

Incorporated in a gelatino-silver-bromide emulsion containing about 4per cent of silver iodide the dye imparts to it a range of sensitivityfrom about 510ml to about 700ml with a maximum at about G/iu.

Further dyes which may be prepared according to the methods described inthe foregoing examples are:

l. [3-ethyl-6 diethylamino-benzthiazole- (2) [S-ethyl benzthiazole (2)]trimethinecyanine perchlorate corresponding with the formula (Gimme/6 7s s 7 6 1| 1,1 1li H I1 I 5 2 2 5 wfo--C 4 I 02H5 C104 01H5 I CH N 7 s s7 z s): le H I? l 6 5 2 2 5 a -C- a 4 N N 4 I :Hl :Hs

Incorporated in a gelatino-silver-bromide emulsion containing about 4per cent of silver iodide the dye imparts to it a range of sensitivityfrom about 520ml. to about 710ML, with a maximum at about 630W..

3. [3-ethyl-6-diethylamino-benzthiazole- (2)[3ethyl-6-ethoxy-benzthiazole- (2) l -trimethinecyanine-perchloratecorresponding with the formula Absorption maximum of the alcoholicsolution: about'603 mi.

Incorporated in a gelatine-silver-bromlde emulsion containing about 4per cent of silver iodide the Vdye imparts to it a range of sensitivityfrom about 500ml to about '730ML with a maximum at about 645ML.

It is to be understood that our invention is not limited to theforegoing examples nor to the specific details given therein. Numerousother embodiments are possible and We contemplate as included within ourinvention all such modications and equivalents as fall within the scopeof the appended claims.

The formulae of the dyes given herein repres- `ent the molecularstructure `of our new dyes so far as to our actual knowledge. If,however; in future it should become evident that the formulae do notexactly correspond to the dyes this fact will not aiect our inventionsince the dyes will be easily identified by the method of producing thesame which has been fully described in the examples. The maxima ofsensitivity of our dyes are all very fiat and the values indicated maynot be regarded too critical.

What we claim is:

1. A photographic material which comprises a silver halide emulsioncontaining a -trimethinecyanine salt which is unsymmetrical when thesalt-forming anion is disregarded and which contains an amino group inat least one of the nuclei.

2. A photographic material which comprises a silver halide emulsioncontaining a carbocyanine salt, which is unsymmetrical when thesalt-forming anion is disregarded, corresponding with the formula (the)quinll'ine nue eus emg W linked in 2 or 4 position) Y =S, Se Y'= Se,C(CH3)2, O /R W=H, N alkyl, alkoxyl R =H, alkyl, aryl, acyl,

X is an anion capable of precipatng a carbocyanine dye.

3. A photographic material which comprises a silver halide emulsioncontaining [3-ethyl-6-diethylamino-benzthiazole- (2) [3-ethy1benzselenazole- (2) l-trimethinecyanine iodide corresponding with theformula 4. A photographic material which comprises a silver halideemulsion containing [3ethyl-6-diethylamino-benzthiazole- (2)[3-ethyl-6ethoxybenzthiazole- (2) l-trimethinecyanine perchlora tecorresponding with the formula:

CzHs C104 02H5 5. A photographic material which comprises a silverhalide emulsion containing [3-ethy1-5-diethylamino benzthiazole (2)] [3ethyl 6- diethylamino benzthiazole (2)] trimethine cyanine perchloratecorresponding with the formula:

(Camm- 6 7 C1415 \Cl04 WALTER DIETERLE. WALTER ZEH.

WERNER ZERWECK.

